#define _CRT_SECURE_NO_WARNINGS 1
double pnx(int n, double x)
{
	if (n == 0)
		return 1;
	else if (n == 1)
		return x;
	else
		return ((2 * n - 1) * x * pnx(n - 1, x) - (n - 1) * pnx(n - 2, x)) / n;
}